This invention relates to an apparatus for attaching belt-like materials onto a forming drum.
Belt-like material attaching apparatus have been known for example, as disclosed in Japanese Patent Application Publication No. 22,619/86. The apparatus disclosed in the Publication comprises a material locating plate and a material restraining arm located forward of a forming drum for gripping a leading end of a belt-like material. A driving mechanism is used for driving the material locating plate and the material restraining arm gripping the belt-like material in unison to the forming drum. A pawl-ratchet is located immediately before the forming drum and adapted to engage the belt-like material to prevent it from returning. A cutting unit is located before the forming drum for cutting the material in width directions. A press roll is employed for pressing the belt-like material supplied immediately above the forming drum against it.
In attaching a belt-like material to the forming drum with the apparatus disclosed in the Publication, a leading end of the belt-like material is first urged against the material locating plate by the material restraining arm to grip the leading end from upper and lower sides. Under this condition, the material locating plate, the material restraining arm and the belt-like material are moved in unison toward the forming drum to supply the leading end of the material to the forming drum. At this time, the pawl-ratchet engages the leading end of the material to prevent it from returning. After the belt-like material is then released from the gripping of the material locating plate and the material restraining arm, these members for gripping are returned to their original positions by means of the driving mechanism. Thereafter, the leading end of the material is pressed to the forming drum by means of the press roll, and the forming drum is rotated through a predetermined angle to attach a predetermined amount of the belt-like material to the forming drum. Then the belt-like material is cut along its width direction by the cutting unit without restraining the belt-like material. Thereafter, the forming drum is again rotated to attach a remaining portion of the cut belt-like material to the forming drum and the leading and trailing ends of the material are jointed on the drum.
With such an apparatus of the prior art, however, the cutting of material is apt to be inaccurate as a first disadvantage because the proximity of the cutting portion of the material is not held during being cut. Since the trailing end of the belt-like material is not held after cutting, the material often undergoes unstable movement as a second disadvantage which would make it difficult to join the leading and trailing ends of the material uniformly. As a result, tires formed by the belt-like materials in this manner are inferior in uniformity.